There are a number of conventional processes for producing direct reduced iron (DRI) from iron ore, including the Midrex® Process (Midrex), the HYL® Process (HYL), and the PERED® Process (MME). As with all of these conventional processes, the PERED® Process converts iron oxide pellets or lumps to metallic iron by exposure to reducing gas at relatively low temperatures within a shaft furnace/reactor. The reducing gas consists of hydrogen and carbon monoxide, and is primarily produced in an external reformer, such as a catalytic reformer. The reducing gas flows upwards in the shaft furnace and is exposed to the descending iron oxide, heating it to reduction temperatures. The process can be used to produce CDRI, HDRI, and/or HBI.
Quoting MME, the most significant features the PERED® Process are:                A continuous system utilizing an uninterrupted flow of reducing gases for the removal of oxygen from the iron oxide feed material and for carburizing the reduced iron.        Minimum fuel consumption by recycling the top gas from the shaft furnace into the process.        The specially designed gas reforming system which uses carbon dioxide and steam, produced during the reduction of the iron oxide, for the catalytic conversion of the natural gas without formation of soot. This obviates the necessity of an external source of oxygen for the partial oxidation of methane.        The special feature is the control of steam percentage which is produced from the waste heat from the flue gas.        Maximum heat recovery by preheating the main air, natural gas and feed gas, and the production of steam through flue gas.        
Again, quoting MME, the equipment used in the PERED® Process includes a “novel” shaft furnace and reformer:                The shaft type metallizing furnace utilizes a continuous process flow at highest known efficiencies. Within the furnace, the pellets descend by gravity and will be metallized by direct counter current contact with reducing gasses in the reduction zone.        In the shaft furnace the iron oxide material is fed from charge hopper by gravity through a dynamic gas seal into distribution pipes, which feed the material into the reduction furnace. The oxide distribution pipes are designed specially to deliver the material on the periphery and at center, thereby maintaining a uniform profile of material in the furnace and to increase the reduction zone volume. The feed rate to the charge hopper is controlled by the discharge rate of the product from the bottom of the furnace.        The shaft furnace is divided in three zones with separate gas systems, the upper zone for reduction, a transition zone for carburizing and in-situ reforming, and the lower zone for cooling.        The reduction zone is specially designed to increase the efficiency, to eliminate fines generation, and to take care of swelling of pellets during the reduction process. The bustle ports, installed in two levels at the bottom of the reduction zone, are of special shape to have better penetration of gas to the burden and for better maintainability. The position of the top gas offtake reduces fines carry over and improves height/diameter ratio.        The reformed gas, containing hydrogen and carbon monoxide at a controlled temperature and ratio, is introduced into the descending burden through a series of ports arranged in two levels around the bottom periphery of the reduction zone. The composition and temperature of the bustle gas can be adjusted independently, if required.        Material flowing through the reduction zone passes into a transition zone prior to entering the cooling zone. This transition zone has sufficient height to isolate the reduction zone and cooling zone gas circuits from each other and to allow independent control.        The transition zone is utilized for in-situ reforming by injecting natural gas at higher and controlled flow rates.        In-situ reforming has several beneficial functions: it carburizes and cools the metallic iron and it uses sensible heat in the metallic iron to heat and reform the natural gas into additional reducing gas and thus increases productivity and overall energy consumption.        Elimination of the water-cooled burden feeder reduces fines generation, drops in burden temperature, and the chances of cluster formation in this region. In this zone there is a specially designed easy flow device called a “China hat” to regulate uniform material flow inside the furnace.        Cooling gas is introduced circumferentially through specially designed nozzles in the lower part of the shaft furnace. This modified arrangement reduces cooling zone height and improves proper distribution of the gas along the burden, which in turn improves efficiency of cooling zone.        At the top of the cooling zone, hot cooling gas is sucked through four off take channels specially designed for uniform utilization of the cooling zone and to reduce fines carryover.        The hot gas from the furnace is then scrubbed, compressed, and recycled after conditioning with NG. The process operates with very high cooling gas CH4 content to optimize the cooling zone efficiency.        The material flow at this zone is regularized by two series of burden feeders which rotate 360 degrees and can be controlled independently for speed, direction, and degree of rotation. These burden feeders are advantageous to regularize the material flow and during trouble shooting.        The reduction furnace operates at moderate pressure with the reduction gas remaining within the furnace system by means of dynamic seals at both top and bottom of the reduction furnace. The raw material entering and the product discharged through the seal legs provide a resistance to gas flow. Inert seal gas generated during firing of the reformer is introduced at elevated pressure into the seal legs. Small volumes of inert gases are vented from the reduction furnace discharge and/or the furnace charge hopper.        The DRI produced is discharged from the furnace bottom via a conveyor system into the storage bins for passivation before being consumed in the electric arc furnace (EAF) or sent to further storage for shipment.        The hot, dust laden top gas from furnace is sent to the top gas scrubber where it is cooled, cleaned, and its water vapor content reduced. Upon leaving the top gas scrubber, the gas stream is split. Approximately ⅔ of the gas is used as process gas, while the remaining ⅓ of the gas is utilized as combustion fuel to heat the reformer.        The water content is minimized from the top gas in top gas scrubber. This in turn reduces the load on process gas compressors as it has to circulate less process gas flow.        The reformer generates reduction gases by reforming natural gas in the presence of a specially designed catalyst.        The required water content for reforming is achieved by adding steam which is produced from the waste heat of the flue gas from the reformer at a controlled flow rate.        The process gas is enriched with preheated natural gas and water in the form of steam to obtain the proper feed gas mixture for reforming. After enrichment, this gas is called feed gas. The feed gas is then heated up to approximately 550° C. by waste process heat.        The preheated feed gas then flows through the reformer and is reformed in multiple heat-resisting alloy tubes containing the specially designed flower type catalysts developed to reform methane with CO2 and H2O with up to 10 ppm (vol.) Sulphur present in the feed gas.        The reformed gas analysis and the temperature of the reformer are automatically controlled. The reformer [allegedly] produces reducing gases with higher H2/CO ratio than MIDREX® reformers, which provides a safe operation of reformer and furnace. The reformed gas temperature is adjusted before entering the reduction furnace as per oxide mix ratio and oxygen availability.        The reformer is fired by multiple burners using preheated air and burning a mixture of top gas fuel recycled from furnace top gas/spent gas and natural gas. The flue gas from the reformer is used to preheat combustion air, feed gas and natural gas, and generate steam in the heat recovery system thereby minimizing the energy consumption of the DR-Plant. The flue gas is exhausted to the atmosphere by a ID fan. A small portion of the reformer flue gas is cooled and is then compressed and used as inert gas throughout the DR plant at various points.        
Further, quoting MME, the alleged advantages of the PERED® Process are:                Moderate operating pressure in the reactor compared to MIDREX and HYL processes to improve the reaction rate and to keep the process simplified.        Higher H2/CO ratio to reduce the risk of clustering inside the reactor furnace and provide safer operation of reformer.        Top gas scrubber with single outlet composition with less moisture content to reduce the load of the process gas compressor.        Steam generation from waste heat recovery to reduce the energy consumption and environmental impacts.        Separate steam addition to control the H2/CO ratio precisely and thus stabilize the reduction gas quality and in turn the product quality.        Safe reformer operation with high H2/CO ratio.        Specially designed catalyst with improved efficiency to produce high quality reducing gases.        Heat recovery system of high efficiency with inverted tube bundles.        Maximum heat recovery by preheating the main air, natural gas, and feed gas and production of steam from flue gas and thus low flue gas temperature to the atmosphere.        Double bustle gas injection ports with provision for injecting reducing gases with two different compositions and temperatures.        Simplified design of bustle port to have better flow pattern and easy maintenance.        Oxide distributor feed legs specially designed for uniform distribution of oxide particle size and increase the reduction zone volume.        Ultra-thin tapered refractory construction in reactor to take care of DRI swelling.        Specially designed top gas off take to improve the efficiency of the furnace and to minimize the fines carryover.        No water-cooled burden feeders in some plants.        Specially designed rotating burden feeders, which can be controlled independently for speed, direction, and degree of rotation, to improve the flow pattern and to perform better as a cluster breaker in case of cluster formation inside the furnace.        Specially designed “China hat” for uniform material flow inside the furnace.        Circumferential cooling gas injection to optimize the cooling zone efficiency.        Specially designed cross-shaped cooling gas offtake to optimize the cooling efficiency and to minimize the fines carryover.        Less furnace height.        Less capital, operating, and maintenance cost.        
What is still need in the art, however, is a DR process that improves upon the conventional “China hat” utilized in the transition zone of the shaft furnace to promote burden/product consistency. This structure typically includes a simple, fixed, upwards-pointing convex flow interrupter or the like over and around which the pellets/lumps flow in the transition zone, theoretically to break up any clumps that form and ensure adequate and uniform mixing and gas distribution.